This two-day conference on ?Highly Fluorinated Compounds ? Social and Scientific Discovery? will examine the social, scientific, political, and environmental health issues raised by older contamination episodes as well as recent discoveries of water contamination and elevated exposures to highly fluorinated compounds, variously called perfluorinated compounds (PFCs) or poly- and perfluorinated alkyl substances (PFASs; we use the latter for familiarity). It will bring together 80-110 scientists; government agency professionals; members of community-based, national and regional environmental organizations; retail and industry representatives; journalists; lawyers; and environmental consultants. This conference will achieve three specific aims: 1) Conduct a conference to examine the complex set of social, scientific, political, and environmental health issues raised by the recent discoveries of water contamination and human exposure associated with high levels of PFASs; 2) Develop educational resources for future research and practice; 3) Disseminate findings and create ongoing web portal for information exchange and data archiving. The high profile case of PFOA contamination by DuPont in the Mid-Ohio Valley resulted in landmark lawsuits and significant research studies that linked exposure to PFOA with high cholesterol, ulcerative colitis, thyroid disease, testicular and kidney cancers, and pregnancy-induced hypertension. PFASs have been the subject of voluntary phase-out initiatives, drinking water advisories, and chemical-specific regulations in multiple state and federal agencies. PFAS sites are a prominent new location of lay engagement. Manufacturers and retailers, pressured by advocacy groups and concerned about the potential for future regulation, have discontinued using some PFASs, but often are switching to other, mostly shorter-chain, PFASs even though there is little information available about potential health effects. In May 2016, the EPA released lifetime drinking water health advisories for PFOA and PFOS combined of 70 parts per trillion, significantly lower than the previous provisional health advisory levels. However, no federal enforceable drinking water standards exist for PFOS or PFOA, and some states have health advisory levels below the EPA advisory level. In terms of relevance to NIEHS? Strategic Plan, this conference aligns with Theme 3: Translational Science, Theme 5: Training and Education, Theme 6: Communication and Engagement, Cross-cutting theme: Collaborative and Integrative Approaches, Goal 5: Identify and respond to emerging environmental threats to human health, Goal 7: Use knowledge management techniques for collaborative EHS, and Goal 11: Promote bidirectional communication and collaboration between researchers and stakeholders. The Organizing Committee will be composed of PI Phil Brown (Northeastern), Laurel Schaider (Silent Spring Institute), Andrea Amico (Testing for Pease), Sylvia Broude (Toxics Action Center), Alissa Cordner (Whitman College), and Courtney Carignan (Harvard T.H. Chan School of Public Health).